JPS61279586A - Fluoran compound and color forming recording material using the same - Google Patents

Abstract

PURPOSE:To obtain a green color forming dye having excellent fastness and a color forming recording material using the same, by applying a color forming dye comprising a specified 3-N-isobutyl-ethylamino-7-phenylaminofluoran to a base. CONSTITUTION:A color forming dye comprising a 3-N-isobutyl-ethylamino-7- phenylaminofluoran of the general formula is applied to the base. The fluoran compound is an extremely excellent green color forming dye, and its excellence in fastness is conspicuously displayed when a pressure-sensitive copying paper comprising it is exposed to light before use. Although the fluoran compound can be solely used to produce a recording material capable of forming a green color, it may be used in mixture with other arbitrary color forming dye. For example, a black color tone can be obtained by using the fluoran compound in combination with a black color forming dye showing a slightly reddish tone upon color development or a black color forming dye which will be turned reddish as a result of light fading.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a green color-forming dye having excellent fastness for use in color-forming recording materials such as pressure-sensitive copying paper or heat-sensitive recording paper, and a green color-forming dye using the same. It relates to a chromogenic recording medium.

[Conventional technology]

Color-forming dyes (hereinafter referred to as "color-forming dyes J
Recording materials based on a color-forming system consisting of a color-forming color (developer) and an acidic substance (color developer) are widely used today as, for example, pressure-sensitive copying paper or heat-sensitive recording paper. In these recording media, dyes that develop black colors are mainly used, but in order to adjust the color tone, green dyes are sometimes used in combination. There is a strong demand for something with excellent durability. In addition, as the speed of communication recording machines such as facsimiles increases, there is a growing need to increase the coloring speed of the heat-sensitive recording paper used in them, and the coloring properties of green coloring dyes that are mixed with black coloring dyes also need to be improved. is requested.

Examples of green coloring dyes include 3-diethylamino-5-methyl-7-dibenzylaminofluoran (hereinafter referred to as compound A) represented by the conventional formula and 5-pyrrolidino-7-phenylaminofluoran (hereinafter referred to as compound A) represented by the formula Hereinafter referred to as compound B) is
Publication No. 4 and JP-A No. 50-9430 or JP-A No. 5
Although these fluoran compounds are described in Japanese Patent No. 0-82127 and have been put to practical use, they do not satisfy current demands in terms of their fastness.

[Means for Solving the Problem] The inventors have discovered that 3-N-inbutyl-ethylamide/-7-phenylamitsufluora/ is a green color-forming dye that is significantly superior in fastness to the above compounds A and B. I discovered something.

The excellent fastness of the fluoran compound of the present invention is particularly noticeable in pressure-sensitive copying paper when the pressure-sensitive paper is exposed to light before use.

Table 1 shows the results obtained using the above-mentioned compound A (color development is green), compound B (color development is dark green), and the compound of the present invention (color development is dark green), which are green color forming dyes currently in practical use. The upper sheets of the pressure-sensitive copying papers produced in Example 1 and Comparative Example 1 were irradiated with light for 60 minutes using a light tester, and the upper sheets were added to the lower sheets before and after the light test, respectively. The color density and color tone of the lower paper surface that has been colored by pressing are measured using a color difference meter, and the values of a and b are recorded.

Table 1 Compounds of the present invention a-10,74-9,621,j
2 5.98b 7.39 8.07 0.
68L 48.2! +56.15 7.92
Compound A a-14,965,39203j, 20
．． 26b 9.93 3.40 452L
42.13 67.28 25.14 Compound B a
-9,08-3゜77 5.30 25.8
4b 5.32 255 -2.79 The value in the table represents the brightness, and the smaller the value, the darker the color. The a value represents the degree of redness of the color tone, and the -a value represents the degree of greenness, and the larger the absolute value, the darker the color tone is. The b value represents the degree of yellowness of the color tone.

ΔL1Δa and Δb are IJfa before and after light irradiation
.

It represents the difference between the a value and the b value, and ΔE represents the total value of changes in brightness and color tone.

In the table, the a value of compound A is from -14,96 to 5.5.
The change to 9 indicates that the color of the pressure-sensitive copying paper before the test was green, but the color of the pressure-sensitive paper after the light exposure test had changed to a red color. Its value is also very high at 20.35.

In Compound B, no significant change in color tone was observed before and after light irradiation as in Compound A, but the L value was 4.
The density increased from 2.13 to 6128, which indicates that the green density of this pressure-sensitive copying paper became significantly lighter due to light irradiation.

The results of observing the colored paper before and after the light exposure test of these pressure-sensitive copying papers are in good agreement with the above measurement results, and for Compound A, the color tone of the pressure-sensitive copying paper after the light exposure test is The color of Compound B on the pressure-sensitive test paper after the light test is green with no significant change in color tone compared to the color before the light test. The paper is so pale that it cannot be put to practical use as pressure-sensitive copying paper.

On the other hand, in the compound of the present invention, there is only a slight change in the L value, a value, and b value due to the light test, and even after the light test, the color development is green, and the color density is also pressure sensitive. It maintains a sufficient density for use on copy paper.

The relationship between the changes in color tone and color density due to light irradiation as described above also applies when clay-coated bottom paper is used as a substitute for the phenol-formalin resin-coated bottom paper used in Example 2 and Comparative Example 1. They appear almost the same.

The fluoran compound of the present invention can be prepared according to a conventional method using 0-(4-N
It is obtained by reacting a 1 molar proportion of -inbutyl-ethylamino-2-hydroxybenzoylbenzoic acid and approximately 1 molar proportion of 4-lower alkoxydiphenylamine in sulfuric acid. The concentration of sulfuric acid used is preferably 80% or higher, and the reaction temperature is preferably 350% or lower. The reaction time requires about 48 hours when the reaction temperature is 20 to 25°C.

The fluoran compound of the present invention can produce a recording medium that develops a green color by itself, but it can also be used in combination with any other color-forming dye. It can be mixed with a color-forming dye or a black color-forming dye that becomes reddish as a result of photofading to achieve black toning. It is also possible to create a recording medium that develops a black color by mixing it with a blue color-forming dye and a red color-forming dye.

Examples of black color-forming dyes that can be used in combination with the fluoran compound of the present invention include, but are not limited to, the following compounds.

3-dimethylamino-6-methyl-7-phenylaminofluorane, 3-diethylamino-6-methyl-7-phenylaminofluorane, 3-diethylamino-6-methyl-7-xylidinofluorane, 3-diethylamino- 6-Methyl-7-p-butylphenylaminofluorane, s ++ :) ethylamino-6-methyl-7-anisidinofluorane, 3-dipropylamino-6-methyl-7-phenylaminofluorane, 3 -di-n-butylamino-6-methyl-7-phenylaminofluorane, 5-N-isopropyl-methylao-6-fk-7
-phenylaminofluorane, 3-N-isobutyl-ethylamino-6-methyl-7-phenylaminofluorane, 3-N-isobenthyl-ethylamino-6-methyl-7-phenylaminofluorane, 3-N -hexyl-
ethylamino-6-methyl-7-phenylaminofluorane, 6-dibenzylamino-6-methyl-phenylaminofluorane, 3-N-methyl-cyclohexylamino-6-methyl-
7-phenylaminofluorane, 3-N-methyl-cyclohexylamino-5-chloro-6-methyl-7-phenylaminofluorane, 5-N-n-pentyl-cyclohexylamino-6-methyl-7-7 22ylaminofluorane, 3-N-methyl-p-tert-butylcyclohexylamino-6-methyl-7-phenylaminofluorane, 3-N-ethyl-31,X,/, S/-trimethylcyclohexylamino -6-methyl-7-phenylaminofluorane, 3-N-ethyl-furfurylamino-6-methyl-7-
Phenylaminofluorane, 3-pyrrolidino-6-methyl-7-phenylaminofluorane, 3-piperidino-6-methyl-7-toluidinofluorane, 3-morpholino-6-methyl-7-p-butylphenyl Aminofluorane, 3-N-methyl-phenylamino-6-methyl-7-phenylaminofluorane, 3-N-ethyl-phenylamino-6-methyl-7-p
-Toluidinofluorane, 3-N-ethyl-1)-)rubidino-6-methyl-
Phenylaminofluorane, 3-α-naphthylamino-6-methyl-7-phenylaminofluorane, 3-dimethylamino-7-N-benzyl-m-trifluoromethylphenylaminofluorane, 3-diethylamino-7- m-trifluoromethylphenylaminofluorane, 6-dinithyla is no 5-ethyl-7-m'-trifluoromethylphenylaminofluorane, 3-diethylamino-5-chloro-7-m-trifluoromethylphenylaminofluoran Oran, 3-dipropylamino-7-m-
Trifluoromethylphenylaminofluorane, 5-di-n-butylamino-7-m-trifluoromethylphenylaminofluorane, 3-N-ethyl-p-
Toluidino-7-m-trifluoromethylphenylaminofluorane, 3-bisridino-7-m-trifluoromethylphenylaminofluorane, 5-pyrrolidino-7-m-trifluoromethylphenylaminofluorane, 5-morpholino-7 -m-) trifluoromethylphenylaminofluorane, 5-N-mef-cyclohexylamino-7-m-trifluoromethylphenylaminofluorane, 3-N-benzyl-cyclohexylamino-7-rn-
Trifluoromethylphenylaminofluorane, 3-N-ethyl-furfurylamino-7-m-trifluoromethylphenylaminofluorane, 5-N-ethyl-furfurylamino-6-methyl-7-
m-trifluoromethylphenylaminofluorane, 3-diethylamino-7-chlorophenylaminofluorane, 5-diethylamino-7-bromophenylaminofluorane, 6-danitylamino-6-chlorophenylaminofluorane, 5-di- n-Butylamino-7-chlorophenylaminofluorane, 3-diethylamino-6-methyl-7-pendylamino-47,5/-benzofluorane, 3-N-methyl-phenylamino-5,6-pendi-twophenoxy Phenylaminofluorane, 3-N-benzyl-phenylami/-5,6-pendi-
Two-phenoxyphenylamino-51,41°51.6
/-tetrachlorofluorane, 5-diethylamino-7
+ Hee? Lysinofluorane, 2-methyl-6-nitylamino-5,6-henzo7
-phenylaminofluorane, 6-diethylamino-6-mether-7-(α-phenylethylamino)fluorane, 6-dimethylamine-7-
(α-phenylethylamino)fluoran, 5-N-butyl-xylidino-6-methyl-7-pendylaminofluorane, 3-pyrolJ di/-7-di(p-chloro7enyl)methylamino Fluoran, 3-methylbi is lysino-7-di(p-chlorophenyl)
Methylaminofluorane, 6-morpholino-5,6-hen7'-7-phenylaminofluorane, 3-N-methyl-cyclohexylamino-5,6-penzo7-α-naphthylamino-4' - Bromofluorane.

In addition to pressure-sensitive copying paper and heat-sensitive recording paper, examples of color-forming recording materials produced using the fluoran compound of the present invention or a mixture of the same and other color-forming dyes include thermal transfer recording paper and electrically conductive heat-sensitive recording paper. , electrophotography that uses toner containing acidic substances as a developer, ultrasonic recording paper, photosensitive printing materials, electron beam recording paper, stamping materials, stamp inks, typewriter ribbons, etc., but is limited to only these. It's not something you can do.

The method for using the fluoran compound of the present invention or a mixture thereof with other color-forming dyes in pressure-sensitive copying paper is the same as that for general fluoran compounds, and is described in US Pat.
No. 548.565, No. 2.548.566, No. 2
, 800,457, specification No. 2,800,458, JP-A-58-112041 or JP-A-58-1
Pressure-sensitive copying paper can be produced according to the method described in Japanese Patent No. 39738.

Pressure-sensitive copying paper consists of an upper sheet that has microcapsules containing a color-forming dye in an organic solvent applied to its lower surface, and a lower sheet that has a color developer (acidic substance) applied and supported on its upper surface. (furthermore, an inner sheet paper carrying the color developer on the upper surface and the microcapsules on the lower surface can also be included in the unit), or the microcapsules and the color developer are coated on the same paper surface. It may be a so-called self-content paper.

As the organic solvent, there may be used an inert and nonvolatile organic solvent that dissolves the color-forming dye well, such as diphenylmethane, alkylnaphthalene, or alkyltriphenyl.

Conventionally known color developers are used, such as inorganic acid substances such as acid clay, activated clay, attapulgite, bentonite, colloidal silica, aluminum silicate, magnesium silicate, zinc silicate, tin silicate, calcined kaolin, and talc. , benzoic acid, 1)-tert-butylbenzoic acid, phthalic acid, gallic acid, salicylic acid, 6-isoprobylsalicylic acid, 3-phenylsalicylic acid, 6-cyclohexylsalicylic acid, 3.5-di-tart-butylsalicylic acid, 6-Methyl-5-benzylsalicylic acid, 3-phenyl-5-(2,2-dimethylbenzyl)salicylic acid, 3,5-di(2-methylbenzyl)salicylic acid, 2-hydroxy-1-benzyl-5-naphthoic acid Aromatic carboxylic acids such as, these aromatic carboxylic acids and zinc, magnesium, aluminum, titanium, etc.*
Gold tts salts, phenolic resin color developers such as p-phenylphenol-formalin resin, p-butylphenol-acetylene resin, mixtures of these phenol resin color developers and metal salts of the aromatic carboxylic acids, etc. can be mentioned.

The method for producing thermal recording paper using the fluoran compound of the present invention is the same as that for known color-forming dyes.
No. 45-14059 or Japanese Patent Publication No. 59-7
It can be manufactured according to the method described in Japanese Patent No. 087 and the like. That is, for example, a suspension in which fine particles of the fluoran compound of the present invention or a mixture thereof with other color-forming dyes and fine particles of an acidic color developer are dispersed in an aqueous solution of a water-soluble binder is applied to paper and dried. By doing so, a thermosensitive recording paper with excellent color development can be obtained. When a sensitizer is added to the above suspension, a heat-sensitive recording paper with extremely high sensitivity can be obtained. The suspension may further contain fillers, dispersants, color image stabilizers, antioxidants, desensitizers, antiblocking agents, antifoaming agents, light stabilizers, fluorescent brighteners, etc. .

Examples of the color developer used at this time include the above-mentioned bisphenol A, 4.4'-secondary butylidene bisphenol, 4.4'-cyclohexylidene bisphenol, 2.2'-i; hydroxydiphenyl, and R-butylidene bisphenol. Bisphenol compounds such as bis(4-hydroxybenzoate), sulfur-containing bisphenol compounds such as 1,7-di(4-hydroxyphenylthio)-5,5-dioxahebutane, benzyl 4-hydroxybenzoate, 4-hydroxy Ethyl benzoate, propyl 4-hydroxybenzoate, isopropyl 4-hydroxybenzoate,
4-hydroxybenzoic acid esters such as butyl 4-hydrogiabenzoate, isobutyl 4-hydroxybenzoate, chlorobenzyl 4-hydroxybenzoate, methylbenzyl 4-hydroxybenzoate, diphenylmethyl 4-hydroxybenzoate, 4-hydroxy -4'-methyldiphenylsulfone, 4-hydro-4/-isoproboxydiphenylsulfone, 4-human hydroxyl sulfone, -4'-butquine diphenylsulfone, dimethyl 4-bitroxyphthalate, Dicyclohexyl 4-hydroxyphthalate, di7-hydroxyphthalate
4-hydroxyphthalic acid diesters such as polyester, ester acids of hydroxynaphthoic acid such as 2-hydroxy-6-carboxynaphthalene, as well as hydroxyacetophenone, p-7 dinylphenol, benzyl 4-hydroxyphenylacetate, Examples include p-benzylphenol and /1-hydroquinone monobenzyl ether.

Examples of water-soluble binders include polyvinyl alcohol, hydroxyethyl cellulose, carboxymethyl cellulose, styrene-maleic anhydride copolymer salt, and styrene-maleic anhydride copolymer salt.
Examples include, but are not limited to, butadiene emulsion, hinyl acetate-maleic anhydride emulsion, polyacrylates, polyacrylamide, starches, casein, gum arabic, and the like.

Examples of sensitizers include higher fatty acid amides, benzamide, stearanilide, acetoacetanilide, thioacetanilide, dimethyl 7-talate, dibenzyl terephthalate, dibenzyl in7-thalate, bis(tart-butylphenol), etc. .4'-dimethoxy7diphenylsulfone, 4-iso~propoxy-4'-n-
Diethers of bisphenol S such as butoxysulfone, 4.4'--)fu)oxydiphenylsulfone, 4.4'-di0-(or 1so-)pentyloxydiphenylsulfone, diphenylamine, carbazole, 2.5 Examples of the filler include clay,
Examples include Merck, kaolin, satin white, titanium oxide, calcium carbonate, magnesium carbonate, barium sulfate, magnesium silicate, and aluminum silicate.

Furthermore, dispersants include sulfoconophosphate esters such as dioctyl sodium sulfoconophosphate, sodium dodecylbenzene sulfonate, sodium salts of lauryl alcohol sulfate, fatty acid salts, etc., and color image stabilizers include, for example, salicylic acid. Derivatives, metal salts (especially zinc salts) of oxynaphthoic acid derivatives, zinc compounds insoluble in pond water, etc. are used as antioxidants, such as 2,2'-methylenebis(4-methyl-6-tert-
butylphenol), 2.2'-methylenebis(4-ethyl-6-tert-butylphenol), 4.4'
-furobylmethylenebis(3-methyl-75-tert)
-butylphenol), 4,4'-thiobis(2-t
ort-butyl-5-methylphenol), desensitizers such as aliphatic high M alcohols, polyethylene glycol, guanidine derivatives, etc., and anti-blocking agents such as stearic acid, zinc stearate, calcium stearate, carna Examples include wax wax, paraffin wax, and ester wax.

In order to use the fluoran compound of the present invention for thermal transfer, for example, JP-A-58-212985, JP-A-59-33,1
No. 85, JP-A No. 59-42,995 or JP-A-Sho 5
It can be used according to the method described in Japanese Patent Publication No. 9-225,986, and for use in energized recording paper, for example,
8-96,137, JP-A-48-101,935, or JP-A-49-11,344, and for use in electrophotography, for example, JP-A-52-24.
, 530 or JP-A-52-56,932.

Furthermore, in order to use the fluoran compound of the present invention for photosensitive recording, for example,
No. 10550, Japanese Patent Publication No. 49-45978, Japanese Patent Publication No. 1973
-80120, JP-A-50-126228, JP-A-52-141633 or JP-A-54-14782
According to the method described in Publication No. 9, French Patent No. 2,120,922 is used for ultrasonic recording, and Belgian Patent No. 959.986 is used for electron beam recording.
It can be used for electrostatic recording according to the method described in Japanese Patent Publication No. 49-3932, and for incorporation into photosensitive printing materials according to the method described in Japanese Patent Application Laid-open No. 48-12104.

Next, examples (manufacturing examples and usage examples) and comparative examples will be described, but the present invention is not limited thereto.

Example 1 A 300 ml flask was charged with 161 y of concentrated sulfuric acid, stirred at a temperature of approximately 10°C, and 161 g of o-(4-N-inbutyl-ethylamino-2-hydroxybenzoyl)benzoic acid and 2 t3 of 4-ethoxydiphenylamine were charged. was added, and the reaction was continued at a temperature of 20-25C for 48 hours. The reaction solution was pressurized into 450 y of ice water, and the precipitated crystals were collected, washed with water, stirred and heated with 3851 tt of toluene, 115 d of water, and 38.5 g of caustic soda, and refluxed for 2 hours. The mixture was left to cool, the aqueous layer was removed, the toluene layer was washed with warm water, and after removing trace amounts of insoluble matter, about 250 a of toluene was distilled off. The residual liquid was cooled, and the precipitated crystals were collected, washed with toluene, and dried to give 3-N-isobut9-,? +/-engine f
k7mi/-7-phenylaminofluorane36.
8F was obtained as almost colorless crystals with a melting point of 171-171.8C.

Example 2 3-N-Inbutyl-ethylamino-7-phenylaminofluorane4. Alkyl Og:) Phenylmethane (
Nisseki Chemical Co., Ltd. “)・Izor SAS 296 J
) 50.0. P and diisopropylnaphthalene (KMC-115J, Kureha Chemical Co., Ltd.) i09 was mixed and heated to dissolve, stirred at 90° C. for 10 minutes, and cooled (liquid A).

On the other hand, 30.0 g of a 10% aqueous solution of sulfonic acid-modified polyvinylalcono (Nippon Gohsenol CKS-50J average polymerization degree of about 300, saponification degree of 97%, degree of modification of 10 moles), ethylene maleic anhydride/acid 10% aqueous solution of polymer (Monsando Co. [Cara-51J)]
5.0I! and water 67, 51117 were mixed, further 5.0 g of urea and 0.5 g of resorcin were added and dissolved, and the pH was adjusted to 3.4 using 20 g of caustic soda aqueous solution (solution B).

Add liquid A to liquid B and mix for 9,000 r using a homomixer.
Stir for 2 minutes at pm to form an emulsion, then at 35 pm.
% formalin aqueous solution 14.0J7 added to 9.000
After stirring at rp+n for 3 minutes, the rotation speed was increased to 8.00 O.
The stirring was continued at a temperature of 60-65° C. for 60 minutes. Stop stirring with the homomixer, cool the liquid temperature to 40℃, add 28 thiammonia water and -Z
5 to obtain a microcapsule suspension.

This suspension (temperature below 60°C) 27.0 u, wheat starch 5.59.8% small wheat flour powder liquid 8.5 and water 34.0
A coating solution was prepared by mixing and stirring M using a stirrer at room temperature for 30 minutes.

This coating solution was applied to white cardboard using a wire <-412 and dried for 6 minutes with warm air at 600 °C to prepare a top sheet of pressure-sensitive copying paper.

The coated side of the upper sheet was placed on the coated side of the lower sheet for pressure-sensitive copying paper prepared by coating and drying phenol-formalin resin, and pressure was applied between two rolls at a pressure of 20 kg/tm2. The coated surface of the lower paper developed a slightly dark green color.

The coated surface of the upper paper was irradiated for 60 minutes using a carbon arc fade meter, and then the lower paper was colored in the same manner as above. Although the green color was slightly lighter than that when the upper paper coated surface was not irradiated, no change was observed in the color tone.

Table 1 shows the measured values of these colors using a color difference meter.

Comparative example 1 3-N-inbutyl-ethylamino- in Example 2
Similar to Example 2 using 6-diethylamino-5-methyl-7-:)benzylaminofluorane (compound A) and 3-pyrrolidyl-7-phenylaminofluorane instead of 7-phenylamino 7A/oran. A top sheet for pressure-sensitive copying paper was prepared, and color was developed on the coated surface of a bottom sheet for pressure-sensitive copying paper in the same manner as in Example 2. The color developed by Compounds A and K was bright green, and the color developed by Compound B was the same color tone as in Example 2, but a slightly darker color.

Further, the coated surfaces of these two types of upper paper were irradiated with carbon arc in the same manner as in Example 2, and the irradiated surfaces were overlapped with the coated surface of the lower paper and colored in the same manner.

The color developed by Compound A was a pale red bean color.

Further, the color developed by compound BK was extremely pale green.

Table 1 shows the measured values of these coloring surfaces using a color difference meter.

Example 6 3-N-Inbutyl-ethylamino-7-phenylaminofluorane 1. Oy and 90 g of 3-N-methyl-cyclohexylamino-6-methyl-7-phenylaminofluorane (black color-forming dye) were mixed. This mixture 3.5.9. SL clay (Engelhard, r UW-904) 15.0
g and 40.0.9 g of pure water using glass beads (diameter 1-1
．． 5) Place the bottle together with 150F in a 250II polyethylene bottle, seal it, and attach it to a Red Devi1 paint conditioner. After shaking at a frequency of 630 times/min for 5 hours, remove the glass beads and remove the additive. An aqueous suspension of A-1 was obtained (Suspension A).

On the other hand, as a color developer, 5 g of bisphenol A Io, 15% aqueous solution of polyvinyl alcohol (same as above) 41
．． 5 g, clay (same as above) 8. op and pure water 40.0.9 with glass beads 150y
The mixture was placed in a polyethylene bottle (No. 1), sealed tightly, and shaken with India conditioner at a frequency of 630 times/min for 8 hours, and the glass beads were removed to obtain an aqueous suspension of bisphenol A (suspension B). .

10 g each of liquid A and liquid B were mixed and stirred for 20 minutes to produce a coating liquid.

This coating solution was applied to white base paper using a wire rod 1612, and dried with warm air at 60°C for 2 minutes to form thermal recording paper I.
was manufactured.

The coated surface of this thermosensitive recording paper was heated for 5 seconds at 150°C using a thermal gradient tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.) to develop color. Its color was a beautiful black. This colored surface was exposed to sunlight for 5 hours, but no significant change in color tone was observed.

By the way, 3-N-methyl-cyclo~xylamide/-6
Thermal recording paper produced in the same manner as above using only 3.52% of Oran was colored black with a slight reddish tinge. there were.

Patented wheat flour Shin Nippon Vinegar Co., Ltd.

Claims (1)

[Claims] 1) 3-N-isobutyl-ethylamino-7- represented by the formula ▲ Numerical formulas, chemical formulas, tables, etc. ▼
Phenylaminofluorane. 2) A color-forming recording material in which a color-forming dye containing 3-N-isobutyl-ethylamino-7-phenylaminofluorane is coated on a substrate. 3) A color-forming dye containing 3-N-isobutyl-2-ethylamino-7-phenylaminofluoran and one or more black color-forming fluoran compounds is coated on a substrate, as claimed in claim 2. chromogenic recording material. 4) The chromogenic recording material according to claims 2 and 3, wherein the substrate is paper. 5) The color-forming recording material according to claims 2 and 3, wherein the color-forming recording material is a heat-sensitive recording paper. 6) The color-forming recording material according to claims 2 and 3, wherein the color-forming recording material is a heat transfer color-forming recording paper.